Wednesday, November 26, 2008

Splendid Isolation

Often the lessons of the past shed light on how to solve the problems of the present. As the title of this post hopefully suggests, the early days of computing were spent in splendid isolation. We didn't connect to each other except through a few shared business applications. There were no PCs, no LANs, no emails and no Internet. And our world was very secure as a result.

The beginning of the client/server era was ushered in with the PC, with communications generally limited to low-speed modems and perhaps a coax connection to maintain compatibility with the mainframe. Data was shared using 5 1/4" floppy disks capable of less than a megabyte of information. But the beginning of the end of isolation had arrived.

The introduction of the aforementioned LANs, emails and Internet ended our splendid isolation and provided the platform for spam, viruses of all types and rootkits, just to name a few, to flourish. And ever since we've been piling on solutions to combat these ills, but rarely striking blows in the proper direction, returning to splendid isolation, architected from the ground up.

In 2003 the MS-Blaster virus infected a large number of PCs, including my work computer, resulting in a few days of late nights, manic patching and shutting off connections to the outside world. Quite the opposite happened with my home computer which was never infected. After restoring service for the company, I reflected on how my professional managed PC, equipped with all the latest anti-virus software, up-to-date patches and protected by world-class Internet firewalls got infected but my home computer, equipped with free anti-virus software and a $50 firewall breezed right through. Was it the luck of the draw?

The answer was the splendid isolation my home computer existed in. MS-Blaster spread from PC to PC across open LAN connections. My home computer simply was all alone. In my work environment there is no need for my PC to communicate directly to any other PC; all sharing is performed via servers and applications in the data center. Yet the LAN is open for no particularly good reason, it just was always done that way. So we can learn from the Internet, where trust is not granted, and extend that same model to our internal networks. Just make it impossible for PCs to talk to each other. Return them to a greater degree of isolation and greatly reduce the chances that an MS-Blaster can spread.

Since the MS-Blaster incident, my home network has grown and now includes a few laptops and a couple desktops. Learning the lesson from the past, I implemented AP (Access Point) Isolation on my wireless router/firewall, which allows Internet access only, once again returning each of my PCs to their own islands of isolation.

Another symptom of lost isolation presents itself with software vendors requiring their own servers to support their products even when their product requires only a portion of its computing power. Dating back to the early days of Windows, applications could easily interfere with each other and the operating system lacked the controls to prioritize workload, isolate memory and insure system stability. So it's not surprising that virtualization solutions, for example VMWare and Xen, have become very popular in the last couple years. While vendors initially resisted supporting their applications in a virtual machine, market realities changed their minds. Emerging cloud computing infrastructures have virtualization at their core as they strive to serve multiple customers on common hardware. While this form of isolation, both from multiple applications and a variety of server hardware, does not solve the problem at its source, it does provide service and risk benefits beyond a modest lowering of the platform cost.

VMWare appliances are an innovative method to deliver software demonstrations or a complete Linux distribution that you can run on a Windows desktop. A secure environment could be developed to enable a corporate desktop to run as a virtual appliance on an employee's home computer, eliminating the need to lug a laptop back and forth to work every day. The benefits of isolation are just beginning to be explored.

Making isolation, in all its various forms, a key technology strategy will lead to lower costs, improved service levels and some welcome relief for your security department.

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